Transition to whistler mediated magnetic reconnection

The transition in the magnetic reconnection rate from the resistive magnetohydrodynamic (MHD) regime where the Alfvén wave controls reconnection to a regime in which the ions become unmagnetized and the whistler wave mediates reconnection is explored with 2‐D hybrid simulations. In the whistler regime the electrons carry the currents while the ions provide a neutralizing background. A simple physical picture is presented illustrating the role of the whistler in driving reconnection and the rate of whistler mediated reconnection is calculated analytically. The development of an out‐of‐plane component of the magnetic field is an observable signature of whistler driven reconnection.